Possession

Possession is the undeniable state of having something.

Alternately, it is an affliction on par with glossolalia in terms of scientific credibility. Supposedly, it is the state of being inhabited by a demonic spirit. Victims manifest many signs of their possession, such as glossolalia, foresight, clairvoyance, telepathy, lethargy, and paranoia. In some cases, an exorcism may be required, in which the power of Jesus Christ our Lord and Savior is used to rid the afflicted soul of the demonic presence.

A good movie to watch on the topic is the Exorcist. Also, Alien. Or any movie with Tom Skerrit.